#include <bits/stdc++.h>

using namespace std;

class StreamChecker
{
private:
    unordered_set<string> s;

public:
    StreamChecker(vector<string> &words)
    {
        for (auto& e : words)
        {
            s.insert(e);
        }
    }

    bool query(char letter)
    {
    }
};